In Lorca's Play Without A Title, a rehearsal of A Midsummer Night's Dream is taking place off stage and figures costumed as characters from Shakespeare's comedy mill around the proceedings. The Prompter announces that he finds this work "very cheerful", whereupon Lorca's "Author" figure robustly disagrees. "But it isn't cheerful," he argues. "Everything in the play tends to show that love, whatever kind of love it may be, is an accident and doesn't depend on us at all. The characters fall asleep, the little spirit Puck arrives, makes them smell a flower, and, when they awaken, they fall in love with the first person who passes by. So the Queen of the Fairies, Titania, falls in love with a peasant with the head of an ass. It's a terrible truth, and a destructive truth can lead to suicide..."

Written around 1935, Lorca's unfinished drama anticipates, in its troubled, uncomplacent angle on the Dream, the sort of interpretation that would become common some 30 years later in the wake of Jan Kott's criticism and Peter Brook's celebrated white-box, trapeze-borne version of the comedy. After all, how should we feel about a play in which one of the couples (Helena and Demetrius) has only managed to become a romantic unit because the male partner is still under the influence of Puck's magic potion? That fact points up merely one of the ways in which the moon-struck interpretation of the play's three worlds - the supernatural realm and the two human spheres (aristocratic and artisan) - remains disturbing even after the supposed resolution. And as for that enchanted wood near Athens, isn't it just the Unconscious avant la lettre and with leaves? Indeed, reviewing a recent foreign staging, Irving Wardle was moved to argue that these days "any self-respecting production ... has to be experimental" because the previously agreed conventions have melted away. "What, in 1991," he asked, "is a fairy?"

Emboldened by these areas of indeterminacy, modern directors have seized on Shakespeare's text as a pretext for exploring contemporary anxieties. In Alexandru Darie's acclaimed Romanian version (a hit at Lift a few years back), the magically monitored, metaphysically shifting world of the play became the eerie mirror of a politically shifty and repressive surveillance state. Oberon's retinue pointedly included four Securitate snoopers in grimy macs. Instead of sticking with the common practice of doubling Oberon and Theseus, the same actor was also used to play Peter Quince, the director of the rustics' amateur theatricals. This had the effect of turning the figure into a sinister split personality, a master-manipulator from whom nothing on any of the play's levels was private.

Evoking, in Darie's staging, a political nightmare from which it was impossible to awake, this blurring of boundaries was taken to the opposite, purely psychological extreme in Robert Lepage's notorious mudbath Dream in the Olivier. Benjamin Britten's operatic version famously opens with glissando chords that mime a sleeper's breathing, as if the whole earth were suspiring in slumber. With the spectacle of the four lovers slumped in a sleeping heap on a hospital bed that was being punted around the enormous dirty pond of a set, Lepage made the hermetic idea of a communal dream-within-a-dream just a shade more unavoidable. Here, the young couples' experience of the magic forest became a literal wallowing in the primordial muck of the collective unconscious. Hello, Jung lovers, so to speak. At dawn, these now inordinately besmirched figures left for the morning light under a row of sprinkling showers, the only surprise being that they weren't put through a car-wash.

In complete contrast, Botho Strauss's 1983 play The Park, which premieres in London at the RSC next week, achieves its revisionary take on the Dream by heightening rather than relaxing the division between the supernatural and human worlds. There was a recent musical, called Another Midsummer Night at the Goodman Theatre, Chicago, in which, during a "post-feminist, post-post-modern, neo-Dadaist, environmental" outdoor production of A Midsummer Night's Dream, the electrical field somehow resummoned Shakespeare's original personnel to the scene. "Four hundred years is a long time to wait for revenge," as the programme rightly remarked, but Titania at last wreaked it on Oberon, by causing him to fall in love with the female performance- artist playing Puck who got trapped, maddeningly beyond his reach, in a video monitor. Set in a rubbish-strewn German city park, representing the unlovely urbanised equivalent of Shakespearian pastoral, Strauss's play also drags the King and Queen of the Fairies into a debased contemporary environment, though with arguably more thoughtful results.

The Park is a "continuation" of the Dream in the same questioning sense as Howard Barker's Seven Lears is a "prequel" to King Lear. Seven Lears follows its hero from boyhood to old age but sends him, morally speaking, in the opposite direction to that laid down by the Bard. Edward Bond's well-known quarrel with Shakespeare's tragedy is that Lear's radical social insights only come when he is too mad and enfeebled to act upon them. Barker's prequel deconstructs that aspect of the play by up-ending it: his king has, to an acute degree, an innate social conscience and spends the seven ages of his life in a frantic effort to distance himself from the responsibility of his insights and to become a sequestered Tolstoy- figure.

Likewise, as The Park's director, David Fielding, puts it, Strauss's play "pulls the questions that have to remain on the periphery of Shakespeare's comedy into the centre". Revenants from a myth they are condemned to repeat but now do not have the power to control, Oberon and Titania are, in her words, "stuck here in the shrubbery, like / A pair of grim old flashers / Cursed to be endlessly exposing ourselves to an / Unenthusiastic world". Peter Stein, one of the great Strauss exponents, has described the play as being about "the different forms of the inability to love and desire". Colliding with the recalcitrant material of the modern world - in which madness is "turned inwards / As [humans] weep and wail over their own shortcomings / But who becomes mad for someone else?" - the myth smashes and goes haywire.

Thematic motifs from the Shakespeare turn up in disaster-warped form. The bestial cruelty of the trick played on Titania via Bottom is gorily exposed by reverting to the legend on which it is based. Here, like Pasiphae, she lusts to be mounted by a bull, achieving her ambition (and becoming a "blood-soaked myth" in the process) through a cow-disguise fashioned by Cyprian, a Puck who has lost his innocence through the corruptions endemic in serving the human art-market. The result of this coupling is the Minotaur, the hybrid monster who stands in this post-1989 rethinking of the piece as an emblem of the reunited Germany. It's little wonder that a disgusted and betrayed Oberon, taking a leaf out of Prospero's book, renounces his magic powers and becomes a middleman in a video company.

A Midsummer Night's Dream carries with it such a weight of interpretative tradition and spin-off art that, in 1988, John Caird could mount a hilarious post-modern production for the RSC that was as much an ongoing commentary on the play's performance history as a staging of the play. (For example, Mendelssohn's incidental music was served up in memorably desecrated fashion and at one point Puck entered reading the Penguin edition which he irritatedly tossed aside.) The flood of by-products shows no signs of abating. Last year, a century and a half after Mendelssohn's composition, there was the premiere of Hans Werner Henze's Eighth Symphony, a work which reflects on three episodes from the comedy. Dislocating the conventions and the ideology of Shakespeare's play, The Park keeps its eye more firmly on the object than many a Dream-derived piece and, in that sense, as David Fielding argues, it is less a disintoxicant than an hommage.